Piano construction.



No. 658,985. v Patented Oct. 2, I900. E. A. &. R. W. GERTZ.

PIANO CONSTRUCTION.

(Application filed Apr. 30, 1900.) (No Model.) 3 Sheets-Sheet l.

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No 658,985. Patented Oct. 2, 1900.

E. A. a R. w. GERTZ.

PIANO CONSTRUCTION.

(Application filed Apr. 30, 1900.) (N0 lludoh) 3 Sheets-Shoat 2.

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-No. 658,985. Patented Oct. 2, I900.

E. A. a n. w. GERTZ.

PIANO CONSTRUCTION.

(Application Med Apr. 30, 1900.)

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.E 560115; Ira/Z1 aa e THE NORRIS was co. PHOTO-UTHO WASNINGTON, 0 cv UNITED STATES PATENT OFFICE.

EMIL AIGERTZ, OF HANOVER, GERMANY, AND RICHARD V. GERTZ, OF CAMBRIDGE, MASSACHUSETTS.

PIANO CONSTRUCTION.

SPECIFICATION forming part of Letters Patent No. 658,985, dated October 2, 1900.

Application filed April 30, 1900- To all w/wm it Jim/y concern.-

Be it known that we, EMIL A. GERTZ. a subject of the Emperor of Germany, and a resident of Hanover, Germany, and RICHARD \V. GERTZ, a citizen of the United States, and a resident of Cambridge, Massachusetts, have invented an Improvement in Piano Construction, of which the following description, in connection with the accompanying drawings, is a specification, like letters on thedrawings representing like parts.

Thisinvention relates to piano construction, more particularly adapted to the grand-piano type; and it has for its object the production of a novel and highly-eiiicient symmetrical rim and sounding-board and string-frame, means being provided for contracting the rim upon which the sounding-board is mounted and secured to thereby maintain the necessary compression of the latter.

in accordance with ourinvention the sounding-board is substantially elliptical in shape, and the frame which supports it is symmetrical in shape, greatly increasing the quality of tone and providing the maximum sounding-board surface, while the adjustment of the frame provides for main taining the sounding-hoard subjected to the necessary compression and for restoring the board to proper compression when circumstances require it.

Figure l is a top or plan view of the outer and inner rims,the sou riding-board and stringlrame being omitted, embodying our invention as applied to a grand-piano construction, the front portion of the piano-frame being merely indicated as forming no part of our invention. Fig. 2 is a similar view showing the string-frame in accordance with our invention, it being understood that the stringframe is mounted upon the inner and outer rims above the sounding-board. Fig. 3 is a longitudinal sectional view on the line a; m, Fig. 2; and Fig. A is a transverse sectional view on the line ac m, Fig. 2.

In accordance with our invention the rim upon which the sounding-board is mounted and secured is symmetrical in shape relative to the longitudinal central vertical plane of the piano and is throughout the greater portion of its extent elliptical in shape, the longer axis of the ellipse coinciding with said cen- Serial No. 14,804- (No modelfi tral plane and, referring to Fig. 1, the centers of the ellipse are located at a a from which the true elliptical portion A A of the rim is derived, the rim being extended forward to the front of the case by the members A A symmetrically from points on the elliptical portion substantially opposite the center a the said members A being connected by a cross-bar A to which the front edge of the sounding-board is secured, the elliptical portion A of the rim being also secured to said cross-bar. 7

The rim is preferably constructed of a series of thin layers of wood glued together, as shown in Fig. 1, and held in shape by diagonal strips or braces (0 of wood, flared at their ends at (t and let into correspondingly-shaped recesses in the rim, these braces being preferably located. between every pair of usual arched sounding-hoard bars I), Fig. 3, and parallel thereto, the arched bars being glued to the under side of the sounding-board in usual manner. These rim-braces a serve to retain the proper compression of the sounding-board, reenforce the anchorage of the arched bars of the latter, and maintain the true shape of the rim, the latter being recessed, as at a Fig. 1, for the arched bars, in which recesses they are glued. The braces 64 are glued to the sounding-hoard, preferably at their ends only, and the board itself is glued around its perimeter to the top of the rim, and the braces are secured to the rim, as stated, so that when the rim is compressed, as will be described, the sounding-board will also be compressed. We have shown herein (see Fig. 1) a series of radiating tension members a preferably thin steel rods headed at their outer ends and passed through the rim, said tension members radiating from the center a toward all the parts of the rim, the heads a resting against the outer face of the rim. A thin steel disk or hell D is located concentric with said center and has an upturned strong peripheral flange (1, provided with holes through.

which the headed inner ends a of the tension members pass, and we have herein shown each tension member as composed of two parts a a which in practice are oppositely threaded at their adjacent ends to receive turnbuckles or nuts a by which the tension of the rods can be adjusted. By such adjustment every portion of the rim and its corresponding section of souriding-board can be compressed and regulated at will, and while it will be obvious that the tension members could be made to extend from one portion of the rim to another portion, passing through the center (0 without the disk or hell D, we prefer to employ the latter for a purpose to be described. The disk or bell can be made of any suitable metal and its body portion is made thin and it can be tuned to a desired interval in harmony with the fundamental tone of the sounding-board before the latter is glued to the rim.

By the employment of the tension members the rim of an ordinary grand or upright piano can be adjusted to compress the sounding board, as described, the sounding-board [3 being shown in section in Figs. 3 and 4c in position on the rim.

Referring to Figs. 1, 3, and 4, the case-bottom R is made of two or more thicknesses of stock, as r r, glued together and of substantially the shape shown in Fig. 1, and on this case-bottom the sounding-board rim, hereinbefore described, and the outer rim are supported, being glued thereto and fastened in any suitable manner, the outer rim C being Separated from the inner rim A A to leave a clearance-space o between said rims throughout substantially the greater portion of the sotuiding-btmrd rim, so that to all intent-s and purposes the two rims are independent. By this novel construction and arrangement the inner rim,with its attached soundingboard, is isolated from the outer rim and the Vibrating capacity of the sounding-board is not in any way interfered with.

Any adjustment of the sounding-board rim by or through the means hereinbefore described will manifestly have no effect on the outside rim 0 tending to change or twist the same, and as such outer rim has, in the construction herein shown and described, no direct effect upon the sounding-board it can be made out of different thicknesses of wood running at right angles to each other, if desired.

In front of the strike (indicated in Fig. 1 by the line S S) the inner and outer rims are shown as rigidly connected together by interposed pieces of wood 0, which extend to the front of the case; but in Fig. 1 a portion of such filling-pieces c is shown in dotted lines, as it would be hidden by the veneering or finishing surface applied to the front ends of the case.

The metallic string-frame is of course subjected to great strain by reason of the attachmentof the strings thereto, and necessarily it must possess strength enough to withstand such strain, and heretofore it has been necessary to make the string-frame very heavy in order to provide the requisite stiffness and strength.

In our present invention we have devised a novel string-framc which may be made throughout the greater part of its area very thin and provided with suitably-arranged strengthening-ribs so disposed as to wit 11st and the various strains to which the string-frame is subjected.

Referring to Fig. 2, the string-frame in its general outline conforms to the outline of the sounding-board rim A A,witb which it is connected in its entire breadth from treble to bass without interruption, said frame comprising flat or web-like portions F, which are located in the. same horizontal [)lzLl]t,lllQ frame being bounded by a deep and rigid flange or strengthcningrib F provided with holes through which are extended the screws f (see Fig. 3,) which securethe said frame to the sounding-board rim around the edges of the board B, the said flange being also pro vided with upturned ears j" to receive lagscrews 5, extended into the outer rim C, by means of which the necessary connection wit h the outer rim is effected.

Referring to Fig. 4-, it: will be noted that adj ustinentof the tension members of the in ner rim to compress the sounding-board is permitted by this construction, as the lag screws .9 are located above the top of the flange F Longitudinal and parallel braces or st i ifeningribs F extend from the transverse front flanged portion F to the arched rear end of the string-frame, and said braces are joined at their rear ends by a pointed arched rib F the apex of which joins the flange F in the longitudinal central axis of the stringframe. Symmetrically-arranged triangular braces or ribs F W, having their apexes at F F, respectively,ou the longitudinal braces F, brace the frame additionally not only in a longitudinal direction, but diagonally and in asymmetrical manner, the system of bracing acting to resist the strain of the strings and to concentrate the same evenly upon the center point a which it will be remembered is also a focus of the elliptical portion of the sounding-board and its supporting-rim. The braces forming the inner sides of the two triangles are joined or intersect each other at the center point, as clearly shown in Fig. 2, and a short longitudinal brace F extends from such intersection forward to the front end of the frame. The intersecting braces forming the inner sides of the two triangles referred to are shown as extended at j b/" respectively, (see Fig. 2,) to the rim-flange F and a transverse brace F extends from one to the other side of the frame to stiffen the latter between the front extremities of the ribs or braces forming the braces or ribs F F forming the outer sides of the two triangles. The hub-like portionf of the stringframe bracing at the center point o provides a support for a bolt (2 which is connected with the center of the bell D, the upper end of the bolt extending above the hub f (see Figs. 3 and 4;) and being threaded to receive an adjusting-nut d, by which the bell may lOO be drawn upward to complete the adjustment of the sounding-board rim and sounding board.

In the completed instrument should the proper com pression of the sounding-board become lessened from any cause, atmospheric or otherwise, it being well known that atmospheric changes are Very liable to affect the sounding-board, the original or requisite compression of the sounding-board and rim may be restored by gradually tightening the adjusti n g-nut d.

The bassbridge l5 and the long bridge B are shown in Fig. 2, the web of the stringframe beingaperi ured, as at F, for the bassbridge, and the position of said bass-bridge and of the bass end of the long bridge is such that the bass parts are symmetrically located relative to each other with reference to the focus a of the sounding-board ellipse, and by this arrangement the vibrating capacity of the sounding-board for'the lower register is tremendously increased.

The wrest-plank WV supports the front end of the string-frame in the usual manner, as shown in Figs. 2 and 3. On Fig. 2 we have indicated by heavy dotted lines the direction in which the strings extend. The bolt (Z is passed up through a small hole if, made in the sounding-board, (see Figs. 3 and 4,) and by reference to the former figure it will be noted that the string-frame is secured to the cross-bar A of the sounding-board rim by downturued ears f one of which is shown in Fig. 3, through which a suitable screw 5 is passed into the cross-bar.

7e have shown herein one practical embodiment of our invention without attempt ing to describe and show various changes or modifications which may be made therein without departing from the spirit and scope of our in vcntion.

Having described our invention, what we claim as new, and desire to secure by Letters Patent, is

1. In piano construction, asounding-board, a supporti ngrim there for to which the sound I ingboard is secured, and adjustable tension members connected with and to compress the rim and thereby regulate the compression of the sounding-board.

2. In piano construction, a sounding-board rim elliptical in shape throughoutthe greater portion of its perimeter, and tension members rat'liating from one of the foci of the elliptical portion to the rim, and means to vary the tension of said members.

' 3. In pianoconstruction,asounding-board, a supporting rim therefor, both arranged symmetrical relatively to the longitudinal center of the piano and elliptical in shape throughout. the greater portion of their extent, arch-bars secured to the under side of the sounding board and to the rim, braces for the latter located between pairs of said archbars and parallel thereto, and means to compress .the rim and thereby regulate the compression of the sounding-hoard.

l. ln piano construction, a sounding-board rim elliptical in shape throughout the greater portion of its perimeter and composed of a series of thin layers of wood cemented together, brace members extended diagonally to the longitudinal axis of the rim, and enlarged at their ends to enter corresponding sockets in the rim, for retaining the shape of the rim, and a series of adjustable tension members radiating from one of the foci of the ellipse to the various parts of the rim to adjustably compress the same.

5. In piano construction, a sounding-board rim substantially elliptical in shape, a soundingboard mounted thereupon and correspondingly shaped, means to compress said rim, and a common controlling device for said means.

6. In piano construct-ion, a case-bottom, inner and outer rims secured thereto independently of each other with a clearance-space between them, a sounding-board secured to the inner rim, and means to regulate the compression of the soui'iding-board by or through. its supportingrim.

'7. In piano construction, a case ,bottom composed of a plurality of layers of wood superposed one upon the other and secured together, an outer rim secured to said casebottom, a laminated inner rim also secured thereto independently of the outer rim, and asounding-board mounted on and secured to said inner rim.

8. In piano construction, a laminated supporting-rim for the sounding-board, diagonal braces anchored in the rim to maintain its shape, a series of adjustable tension members anchored at their outer ends in the rim and converging toward a common point, a metal disk having an upturned flange to re ceive and hold the inner ends of the tension members, and means to vary the tension of said members.

9. In piano construction, a sounding-board rim, a sounding-board supported thereby, both symmetrically shaped relative to the longitudinal central axis of the piano and elliptical in shape throughout the greater portion of their extent, a string-frame secured to said rim above the sounding-board and similarly shaped, a pointed arch-brace for said string-frame at the arched end of the latter, and trianglar braces,the inner sides of which intersect one of the foci of the elliptical portion of the rim.

10. In piano construction, a metallic stringframe, comprising a web portion and braceribs, the greater portion of the frame being elliptical in shape, said braces comprising two longit udinal parallel ribs extending from front to rear of the frame, the two triangles having their apexes on said longitudinal ribs and with their in ner sides intersecting at one of the foci of the elliptical portion.

11. In piano construction, a string-frame, syinnletrical relative to its longitudinal central line and elliptical in shape throughout the greater portion of its extent, said frame having an edge flange or rib, longitudinal and diagonal brace-ribs, the latter forming triangles the inner sides of which intersect, and a pointed arch-brace connecting the triangles.

12. In piano construction, separated inner and outer rims, a case-bottom to which they are secured, a sounding-board mounted on the inner rim and conforming in shape substantially thereto, a metallic string-frame having at its edge a stiItening-rib and upturned ears at the top of said rib, means extended through said rib to secure the frame to the inner rim, connections between the upturned ears of the stiffening-rib and the outer rim, and means to compress the inner rim and thereby maintain the desired compression of the sounding-board.

13. In piano construction, inner and outer rims symmetrically shaped relative to the longitudinal central axis of the piano, means to secure said rims together in front of the strike, the rims being separated and disconnected throughout the remainder of their extent, a sounding-board mounted on the portion of the inner rim separated from the outer rim, means to compress such portion of the inner rim to regulate the compression of the sounding-board, and a case-bottom to which the inner and outer rims are independently secured.

let. In piano contruction, a symmetrical inner rim elliptical in shape throughout the greater portion of its extent, and correspond ingly-shaped sounding-board, and a stringframe, both mounted on and secured to said rim, adjustable tension members anchored at their outer ends in the rim, a circularlyflanged disk concentric with one of the foci of the elliptical portion of the rim, the flange receiving and holding the inner ends of the tension members, a hub on the string frame also concentric with said focus, a threaded bolt secured to the flanged disk and upturned through said hub, and an adjustingmut 011 the upper end of the bolt whereby the compression of the rim may be varied to adjust the sounding-board.

15. A metallic stringframe for pianos, comprising a fiat or web portion, a stiffeningrib around the perimeter of the frame, the latter being elliptical in shape for the greater portion of its extent, two parallel longitudinal brace-ribs, diagonal brace-ribs forming two triangles having their apexcs in the ion gitudinal ribs, and their inner sides intersecting at one of the foci of the elliptical portion, and a pointed archrib springing from the longitudinal ribs and syn'imetrically located relative to the other focus of the ellipse.

16. A metallic string-frame for pianos, having a stiitening-rib around the perimeter of the frame, the latter being elliptical in shape for the greater portion of its extent, two parallel longitudinal brace-ribs, diagonal braceribs forming two triangles having their apexes in the longitudinal ribs, and their inner sides intersecting at one of the foci of the elliptical portion, a pointed archrib springing from the longitudinal ribs and symmetrically located relative to the other focus of the ellipse, and a short longitudinal brace-rib extending from theintersection of the inner sides of the triangular braces to the front edge of the frame.

17. In pianoconstruction, asounding-board rim, tension membersconnected with said rim, and means to vary the tension of said members.

18. In piano construction, asounding-boal'd rim, a sounding-board, arched bars secured to the under side thereof, and a series of straight braces or bars attached at their extremities to the rim and running parallel to and between the arched bars, said straight braces being connected with the soundingboard at their ends to positively retain the arch of the board.

19. A case-bottom, and inner and outer rims independently secured thereto and separated one from the other, to leave a clearance-space between them.

20. A casebottom, separated inner and outer rims independently secured thereto, with a clearancespace between them, a sounding-hoard mounted on the inner rim, and means to compress said rim to maintain the desired arch of the sounding-board.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

EHIL A. GERTZ. RIOI-ID. IN. GERTZ. 

